Hollow mortising-chisel.



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No. 824,673. PATENTED JUNE 26, 1906.

B. G. ROCKWELL. HOLLOW MORTISING CHISEL.

APPLICATION FILED SEPT. 21, 1905.

UNITED STATES PATENT OFFICE.

HOLLOW MORTlSlNG-CHISEL.

. Specification of Letters Patent.

Patented June 26, 1906-.

7 Application flled September 21, 1905. Serial No. 279,532.

To a w/wm it may concern.-

Be it known that I, BYRD O. RooKwELL, a citizen of the United SlEZfCGS IBSidlIIg at Gifford, in the county of Hot Spring and State of Arkansas, have invented a new and useful Hollow Mortising-Chisel, of which the following is a specification.

This invention relates to hollow mortisingchisels.

The object of the invention is in a novel and practical manner to cause the chisel, in addition to forming a mortise, to form air-escape and glue-receiving channels, whereby the scoring, grooving, or threading of dowelpins to permit the escape of air from the mortise and the even spreading of the glue is obviated.

A further object is to reinforce the chisel at its Weakest part, whereby its life will be measurably increased and its utility thus enhanced.

With the above and other objects in view, as will appear as the nature of the invention is better understood, the same consists in the novel construction and combination of parts of a hollow chisel, as will be hereinafter fully described and claimed.

In the accompanying drawings, forming a part of this specification, and in which like characters of reference indicate corresponding parts, Figure l is a view in perspective of a hollow mortising-chisel constructed in accordance with the present in ention. Figs. 2 and 3 are end views of slightly-modified forms of chisel.

In the form of the invention shown in Fig. 1 the chisel 1 is quadrangular in cross-section and is provided with the usual head 2 for connection with a percussive machine and with a slot 3, through which the chips formed by the auger or bit (not shown) escape. Each face of the chisel is provided with a fin or rib 4, which is shown as triangular in cross-section, although it ma be of any other desired contour, and exten s throughout the len th of the bit portion of the chisel. These fins operate to cut grooves in the walls of the mortise as the chisel descends, thereby providing a means by which air can escape when a tenon is driven into the mortise, thereby to in cross-section, is provided with but a single fin 6, while the chisel 7 (shown in Fig. 8) is provided with two of the fins 8. Instead of having the fins oppositely disposed, as shown in this figure, they may be arranged on contiguous sides of the chisel, and as this arrangement will be readily understood detailed illustration thereof is deemed unnecessary.

As is well known, chisels of this character are made in various shapes-such as uadran ular, rectangular, diamond shape, r 0mboi a1, and the like-and it is to be understood that the present invention is adapted to any form of hollow chisel that may be constructed.

Havingi thus described the invention, what is claime is 1. A hollow mortising-chisel provided ex teriorly with an air-channel-forming rib or 2. A hollow mortising-chisel having one of its faces provided with an air-forming rib or fin that is approximately triangular in crosssection.

3. A hollow mortising-chisel rovided eX- J. E. YOUNG, WILLIAM R. DUFFIE. 

